Levi heywood



Letters Patent No. 80,627,1Zated August 4, 1868.

. IMPROVEMENT IN MACHINES FOR BENDING WOOD.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, LEVI HErwOOD, of Gardner, in the county of Worcester, and State of Massachusetts,

have invented certain Improvements in Machines for Bending Wood, of which the followingis a-i'u'll, clear,

and exact' description, reference being had to the accompanying drawings, making part of this specification, in which- 'Figure 1 is a front eleva-tion of my improved machine, the chain being represented as open for the recep-` tion of the timber before being bent.

Figure 2Yis a horizontal section on the line w a: of tig. l.

Figure 3 is a horizontal section throughV the timber'after being bent, and before the chain is removed.

Figure 4 is a. vertical section on the line 3/ y of g. 3. i

In the operations of bending wood by the employment of apparatus as heretofore constructed, it has always been customary to commence bending at and from' the centre toward the ends, or from one end only toward its other end. By these methods, however, the end-pressure of the fibres on the strap accumulates so rapidly as to require a means for relaxing the same.

My invention has for its object to remove or relieve, as far as possible, thisend-pressure on the straptand my invention consists in bending the ends of the wood simultaneously around toward the centre, in contradistinction to bending it from the centre toward the ends, or continuously from one end to the other, the ends ofthe timber being secured to a pair of blocks resting on tables, which are made to move in slots, at 4equal rates of speed toward each other, the said blocks, when united, constituting the pattern or formerot theshape desired to give the timber, the blocks or sectional formers being kept up to and rolling upon the face of the timber, and being -prevented from Slipping away therefrom in the slots, by gearing on the exterior of the tables, engaging with a rack provided with corresponding gear, by which construction the timber is bentifrom the ends only as fast as the foi-mers are rolled over its outer face, the friction or pressure ofthe farmers thereon being such as to relieve, in a great degree, the pressureordinarily exerted by the ends ot' `the timber on the abutments of 'the strap or chain, and causing the fibres to be upset uniformly throughout the length of the stick, :ts-desired.

'.lo enable others skilled in the art to understand and use my invention, -I lwill proceedto describe themanner in which I have carried it ont. i i l' In the said drawings, A is the framework of my vimproved machine, in which are formed slots, a a, of the curvature shown, through which pass the upright studs or shafts 6, upon which are revolved the beds or tables` e e, over the upper ends of which tfthe blocks B B, which, when united, as shownin iig. 3, constitute' the lpattern, C, of the shape desired to be giventhe timber.v D is a stationary toothed rack, into which engage cogs or teeth formed on the exterior surfaces of the-beds or tables c c, in order to prevent the sectional fermiers from slipping in their slots when the ends of the timber secured theretoare being rolled, and bent around thereon, by operating the r'ods or levers E E, screwed into the lower ends of the shafts b b. F F are two arms coni nectcd to a central link, G, by a metal plate or strap, d, in such manner as to form a flexible joint, thc whole constituting a back or support for the chain H to bear upon, the centre of the said chain being screwed at e to the link G, and being advanced in the direction of the arrow 5, or drawn back inl the direction ofthe arrowV 6, by operating a screw, I, the endfof which is rounded ofi' in the form of a cylinder, which enters a recess, g, in the bottom of 'the strap d, and in the back Vof' the link G, a smooth groove, h, surrounding the screw between the cylindrical portionfandthe screw-thread, by whichl construction, as the screw is turned out of its nut J, the eylindricalpcrtionfis brought against the edge of the recess g, inside oi" the metal plate or strap d, which thus prevents it from escaping, and the centre link G, with the ends of the arms F F, and chain H, connected therewith, are drawn back,to allow the timber K, with its strap L, to be placed therein. When the rack or support, with the chain and timber K therein, is pressed in the direction of the arrow 5, by turning-the screw I into its nut J, the smooth portion of the end t ot' the screw-thread comes in contact with the outside of the metal plate d, and carries theparts forward, into the position seen in fig. 2.

In placing the timber within the chain, previous to being bent, the ends of the timber rest against slices or abutments, le, at the extremities of a thin metal strap, M, the outside of' each abutment being provided with a projection, 7, over which is hooked the end ofthe chain, also provided with ametal strap. Each ofthe blocks or sectional formfrs B is provided with a recess, Z, and each end of the back or support of the chain is also provided with a recess, m, to admit the ends of a metal clamp, 8, Vfor holding the ends or abutments of the strap M (with the chain hooked o ver them) snugly up to the formers B, preparatory to-rolling them yover the face of the timber, by which means the timber is kept straight (against the back or support) from its centre outward, while its ends are gradually curved around with the formers toward its centre', thelvertieal planes passing in contact with vtheir outer edges, 9 to 10, when united, constituting the pattern, C, of the shape desired to give thc timber. When thus united, the two sectional farmers are securely held together by a clamp passing into the two recesses l Zat their ends. As the strain of' tlie'timber comes upon the strap, the chain may now be readily removed by simply prying or unhooking its ends from the projections 7 7, on the shoes or abutments c, when the sectional formers, with the bent timber confined thereon by the strap M, are free to be lifted from their tables, c, which are then ready to receive a new pair of formers.

-' The outer ends of the arms E E, forming a part of the back or support 4for the eh'ain, are screwed to the top ofthe framework at n u, the holes o o, provided for the passage of the screws p p, bei-ng of an oblong form,v

as shown, to allow the said ends to be moved back in the direction of the arrow G, to accommodate a chain with a timber of greater width. The form of the slots a a in the framework, for the shafts b 11 to slide in, is determined by the outline of the formers, and consequently by the shape of the pattern desired; for instance, if the timber were to be bent in a circular ferm, each sectional former B would be 'sen1icireular, and the' slots a a would be made straight. The ends of the piece of wood, when bent around the sectional formers, do not abut each other, the thicknesses of theshoes of the strap intervening, but when removed from the formcrs, and the strap is liberated therefrom, the contraction consequent on the drying of the wood will cause the space between its ends to close, and tliey will then snugly unite andit together, making a continuous curved'piece, suitable for chair-seats, or for a variety of other purposes.

By the employment of my improved apparatus, above described, the ends of the timber are simultaneously and symmetrically bent .around toward thc centre, Athe portion of the timber not in contact with the formers remaining straight in the chain, against the back or support, u ntil acted upon by the said formers, the friction or pressure of which upon the timbeiis suiiicient to immediately relieve or remove a considerable portion of the pressure of the ends on the strap, on the commencement of the operation of bending, and the fibres of the stick are thereby upset uniformly throughout its length, as desired, without the necessity of relaxingits ends.

Instead of-thc faces ofthe formers being-smooth, as'herein shown and described, they may be grooved, for the Y reception of 'the inner face of the timber, by which means I am effectually enabled to prevent the said inner face from undulating or crippling In the foregoino description, I have casually spoken ofv the chain I-I, but as it is particularly described in an application of M. V. B. Howes, made simultaneously with this, and forms no part of my invention, it is unnecessary to enter into the details of its construction here.

, Claim.

What I claim as my invention, and desire to secure by Letters Patent, i's- 1. Commencing to bend the wood from each end toward its centre, instead' f commencing to bend it from the centre toward the ends; or from onecnd toward its other end, substantially as and for the purpose described.

2. The formers B B, with the geared tables c c, working in the rack D, and guided by the slots a a, in combination with a suitable chain, H, substantially as and for the purpose described.

LEVI HEYWOOD. Witnesses:

N. W. STEARNS, W. J. CAMBRIDGE. 

